on tuesday president obama addressed the general assembly. he urged world leaders to reject extremism citing the murder of the u.s. ambassador in libya and three others. >> i would like to begin today by telling you about an american named chris stevens. >> reporter: the president told world leaders that the slain u.s. ambassador to libya, chris stevens, had gone to benghazi to establish a cultural center and help modernize a hospital. >> today we must declare this violence and intolerance has no place. >> reporter: it's still unclear what motivated the terrorist attack but president obama focused on that anti-muslim video made in california explaining why the u.s. can't and won't ban a movie that mr. obama himself described as crude and disgusting. >> i know that not all countries in this body share this particular understanding of the protection of free speech. we recognize that. but in 2012 at a time when anyone with a cell phone can spread offensive views around the world with the click of a button, the notion that we can control the flow